1. Field of the Invention
The invention relates to a sensing device, and more particularly to a sensing device with a high signal-to-noise ratio (SNR).
2. Description of the Related Art
Currently, low power consumption is important for electronic apparatuses, especially mobile electronic apparatuses. Light-sensing devices are usually disposed in electronic apparatuses, such as mobile phones and mobile computers, to reduce power consumption of display panels. The light-sensing devices sense environmental brightness and generate control signals according to the sensed environmental brightness. Specifically, light-sensing devices control brightness of display panels of electronic apparatuses, so that the display panels do not always show images by high brightness, thus reducing power consumption. In dark environments however, noise affects of the light-sensing devices are increased due to the decrease in photo currents generated by photo elements of the light-sensing devices. Thus, control signals of light-sensing devices are affected by the noise, resulting in reduced signal-to-noise ratios of the light-sensing devices. Accordingly, brightness of display panels comprising the light-sensing devices are not effectively controlled to reduce power consumption.
Thus, it is desired to provide a light-sensing device which can filter high-frequency noises to increase the signal-to-noise ratio of light-sensing devices.